Implementation of the Heinrich Spatial Visualization Test in a Virtual Environment

A virtual environment was developed for PC and Android to be used with a desktop display and the Gear VR, respectively. The goal with it is to measure and enhance the spatial skills of people, because the latter can be achieved by solving simple geometric problems. Originally, this virtual environment consisted only of three such tests, namely the Mental Rotation Test, Mental Cutting Test and Purdue Spatial Visualization Test. Measurements were done in the past with these tests, but now the Heinrich Spatial Visualization Test is also included in the virtual environment. In this paper, its implementation and future measurement plan are presented.

Identification for Abutment Stress by Drilling Cuttings

The concentration of abutment pressure acting on coal seams induced by mining is a key factor to trigger rock burst. Understanding of abutment pressure or stress concentration is fundamental in preventing and controlling rock burst. The influence on abutment pressure fluctuation caused by the inhomogeneity of coal seams needs to be considered, but it is difficult to obtain by the present usual ways such as acoustic transmission, electromagnetic wave transmission, etc. In this article, the relationship between the amount of cuttings drilled in a coal seam and stress level was analyzed by considering the effect of drilling cutting expansion, and the drilling cutting test was carried out in Xinglongzhuang Coal Mine, Shandong Energy Ltd. It is found that the amount of cuttings drilled is positively related to the degree of stress concentration in both the plastic fracture zone and elastic zone. The amount of drilling cuttings is closely related to the roof weighting. In addition, the irregular fluctuation of drilling cuttings is an approximate map of distribution of stress concentration because of the non-uniformity of cracks and other defects in the coal seam. In order to meet the need of rock burst prevention by accurate pressure relief in high-stress zones, enough boreholes are needed.

Analysis and Experiment of Cutting Mechanical Parameters for Caragana Korshinskii (C.K.) Branches

In order to investigate the cutting mechanical characteristics of Caragana Korshinskii (C.K.) branches and explore the optimal combination of cutting parameters to support the subsequent equipment development, this paper explores the relationship between branch diameter D, average cutting speed v, wedge angle β, slip cutting angle α, cutting height h, cutting gap t, moisture content M and peak cutting force by using a homemade swing-cut branch cutting test bench with peak cutting force of branches as the target value under unsupported and supported cutting methods, respectively, through single-factor tests. Based on the single-factor test, v, β, α and t were selected as the test factors, and a multi-factor test was conducted with the peak cutting force as the target. Test result: The best combination of unsupported cutting in the range of multi-factor test is v for 3.315 m·s−1, β for 20°, α for 20°, when the peak cutting force is 95.690 N. Supported cutting multi-factor test range to get the best combination of v for 3.36 m·s−1, β for 20°, α for 20°, t for 1.38 mm, when the peak cutting force is 53.082 N. The errors of the predicted peak cutting force and the measured peak cutting force of the obtained model were 1.3% and 3.9%, respectively, which prove that the cutting parameters were optimized reliably. This research can provide a theoretical basis for subsequent development the C.K. harvesting equipment.

Using uniform design and regression methodology of turning parameters study of nickel alloy

The nickel alloy has good mechanical strength and corrosion resistance at high temperature; it is extensively used in aerospace and biomedical and energy industries, as well as alloy designs of different chemical compositions to achieve different mechanical properties. However, for high mechanical strength, low thermal conductivity, and surface hardening property, the nickel alloy has worse cutting tool life and machining efficiency than general materials. Therefore, how to select the optimum machining parameters will influence the workpiece quality, cost, and machining time. This research will be using a new experimental design methodology to the cutting parameter planning for nickel-based alloy cutting test, and used the uniform design methodology to cutting test to reduce the number of experiments. Three independent variable parameters are set up, including cutting speed, feed rate, and cutting depth, and four dependent variable parameters are set up, including cutting tool wear, surface roughness, machining time, and cutting force. A nickel alloy turning parameter model is built by using regression analysis to further predict the I/O relationship among various combinations of variables. The errors between actual values and prediction values are validated. When the cutting tool wear (VB) is 2.72~6.18%, the surface roughness (Ra) is 4.10~7.72%, the machining time (T) is 3.75~8.82%, and the cutting force (N) is 1.54~7.42%; the errors of various dependent variables are approximately less than 10%, so a high precision estimation model is obtained through a few experiments of uniform design method.

HIGHLY RESPONSIVE AND ACCURATE TEMPERATURE MEASUREMENTS IN ORTHOGONAL CUTTING THROUGH INNOVATIVE SINGLE LEG THERMOCOUPLE

During machining, most of the thermal sources are resulting from the conversion of mechanical energy during the chip shearing mechanism and the intense frictions between the tool, the chip, and the machined surface. Thermal gradients are high and localized, especially for low thermal diffusivity material like titanium alloys. Moreover, heat rates come close to few million degrees per second in the shearing zones. Even though several authors performed thermography techniques to determine the temperature distribution into the machined material, their results remain underestimated due to experimental limitations. In this research, a new temperature measurement technique has been developed based on a single wire thermocouple to measure at one exact location both the temperature and the heating rate during orthogonal cutting test. The tests are performed with uncut chip thicknesses of 0.020 mm and 0.100 mm and with a cutting speed of 120 m/min with two different cutting angles. Results are discussed and compared to prior studies.

EXPERIMENT AND PARAMETER OPTIMIZATION OF ROOT-CUTTING FOR TRIMMING POSTHARVEST CABBAGE

Trimming for postharvest cabbage is useful to increase its economic value added. For obtaining the optimal root-cutting parameters, a root-cutting test platform based on universal testing machine was designed. Then shear contrast test and orthogonal test were carried out respectively, and shear properties were explained according to root morphology obtained by scanning electron microscope (SEM). The results showed that the effect of sliding-cutting with single-edged cutter was the best. The optimal parameters of cutter thickness, shear position, shear speed and sliding-cutting angle were respectively 0.89 mm, 0.00 mm, 388.94 mm/min and 34.84°, and the shear stress was 28.02 kPa.

Influence of Weakening Groove on Cutting Results of Composites Subjected to Shaped Charge Jet

Carbon-fiber-reinforced polymer (CFRP) has been widely used in aerospace structures for its high strength to weight ratio and high stiffness to weight ratio. However, current pyrotechnic separation devices are mainly made of metal materials, the cutting research on CFRP composites is limited, and the effect of weakening groove on cutting results of composites is unclear under the action of shaped charge jet. In this paper, there firstly established a three-dimensional model of explosive cutting of CFRP composites by nonlinear finite element analysis (FEA), and based on the separation time, delamination, and kinetic energy of the laminate, the influence of weakening grooves on cutting results to the laminate is discussed. The results show that, in contrast to laminates with weakening grooves, laminates without weakening grooves increase the delamination of laminates. At the same time, here, we carried out the explosive cutting test on CFRP composites to verify the rationality of the simulation model. In addition, in order to obtain a better model under the action of shaped charge jet, we optimized the width and height of weakening groove by simulation calculation. Therefore, it proves that this study can guide the application of CFRP composites subjected to shaped charge jet in aerospace separation engineering.

The Effect of Adding Citronella Oil (Cymbopogon nardus) on Edible Coating from Chitosan towards Organoleptic Characteristics of Pempek

The purpose of this research was to determine the best concentration of citronella oil on the edible coating from chitosan towards the organoleptic quality of pempek. This research used an experimental method consisting of 5 treatments: without edible coating (control one), addition of citronella oil with a concentration of 0%, 1.5%, 2.5%, and 3.5% using 20 panelists as replications. The parameters observed in this research were organoleptic characteristics (appearance, texture, aroma, taste, teeth cutting test, and folding test) based on the panelists' preference level using a hedonic test and chemical analysis (water content and fat content) and shelf life of pempek for each treatment. Chemical test data were analyzed descriptively while the organoleptic test results were analyzed using the Friedman test. Based on the Friedman test, it was found that pempek edible coating chitosan with the addition of citronella oil up to 2.5% is still preferred by panelists with a water content on 1st day was 53.08% and on 4th day was 53.05% while the fat content on 1st day was 1.46% and on 4th day was 2.72%. Based on the Bayes test, taste is the most important criterion compared to appearance, texture and aroma. Pempek edible coating chitosan with the addition of citronella oil has a shelf life of up to 4 days.

Changes in gel forming ability and protein solubility of pangasius (Pangasianodon hypophthalmus) muscle at different rigor stages during storage at room temperature (28 to 32°C) and in ice

Gel forming ability of fish muscle is greatly influenced by the storage temperature and rigor stages.The present study was carried out to assess the changes in gel forming ability and protein solubility ofpangasius (Pangasianodon hypophthalmus) muscle stored at room temperature (28 to 32°C) and in ice. Rigormortis in fish sample kept at room temperature (RT) and in ice started 1hr after death. The rigor-indexreached a maximum 73.33% within 7 hrs after death at RT and a maximum 87.09% within 4 hrs in icestorage. At pre-rigor stage, the breaking force (BF) was 646.00 (±2.08g) which decreased to 266.67(±3.53g) at post rigor stage at RT and from 660.33 (±1.45g) to 420.67 (±1.45g) in ice in one step stage. AtRT, grade of folding test (FT) decreased from “AA” to “A” and score of teeth cutting test (TCT) from 8 to4. In ice also grade of FT and score of TCT decreased. Similarly, in two-step heating gels, BF decreasedfrom 994.33 (±2.33g) to 403.00 (±1.15g) at post rigor stage at RT and 995.33 (±1.45g) to 552.67(±3.71g) in ice. Immediately after catch myofibrillar protein solubility was 86% which declined below 30%after 24h of storage at RT and below 30%after 28 h of storage in ice. The study concludes that the rigorperiod of pangasius may be extended up to 18 h by storing the fish in ice while at RT this period is only about5 h, which might contribute to slow down the gel degradation process.